The calculation of gestation days begins on the first day of fertilization of the egg from a male sperm. This procedure usually occurs on the 12th or 13th day of the last menstrual cycle of the woman. However, the women always calculate the date of their last menstrual cycle. Pregnancy This is a common mistake, since in the first ten days there was no pregnancy in them. Thus, the best calculation for the date of pregnancy is the addition of twelve days to the date of the last menstrual cycle; from which begins the calculation of days and weeks of pregnancy.
Pregnancy lasts an average of forty weeks, from the date of pregnancy determination to the date of birth. There is no precise account that can determine the date on which a child will be born, but all are accounts for the expected time of delivery; often more than or less than one week, but it may be up to doctors to resort to so-called forced birth, Overwhelming the woman in her pregnancy, which may negatively affect the life of the fetus, forced birth in this case is an unavoidable solution. The calculation of the weeks is based on the fact that each week is seven days, starting on the day the pregnancy is determined; it ends on the day preceding the following week. For example, if Saturday is defined as the day on which the pregnancy occurred, From Saturday to Friday, and the next Saturday is the first day of the second week and so on.
Some doctors divided the pregnancy period into three stages. Each stage consisted of thirteen (13) weeks; with a week to the last period, the period became forty weeks. Weeks from the first week to the fourth week are the first month of pregnancy, the weeks from the fifth week to the eighth week are the second month of pregnancy; the weeks from the ninth to the thirteenth weeks are the third month. Do not get the last month of five weeks and not four, so that the calculation of weeks of pregnancy coincides with the months. In the second period, the calculation of the weeks as in the first period is a total of thirteen weeks. And the third and last period is calculated on the same system; with the increase of one week to the last month; the maximum pregnancy period for women, where the start of the date of birth with the entry of women in the thirty-sixth week (36) of pregnancy is the beginning of the ninth month on the method of calculating weeks, From this date she can put her baby on any day in the next four weeks.